1. Field of the Invention
The present invention relates generally to vacuum systems, and more particularly to vacuum systems associated with multiple work areas.
2. Description of the Prior Art
Many industries use equipment which in operation generates atmospheric contaminants, which might be gases or airborne particles. These gases and particles are sometimes a health hazard to the operator, as well as to other employees and the environment in general. This problem is especially acute in industrial operations such as wood-working or painting, where dust and gases that are harmful if inhaled are generated in close proximity to the worker. Additionally, particulates can eventually build up and damage equipment in the work area, and often require regular cleaning of the work area. Government regulations in many instances now strictly regulate the amount of such gases and particles which can be present in or emitted from the work area.
Vacuum systems have been installed to withdraw airborne contaminants generated in such work areas. A single vacuum source is usually provided. A manifold usually communicates between the vacuum source and a number of vacuum conduits, the conduits extending to individual work areas. Vacuum openings in the vacuum conduits are provided at the work areas to permit the withdrawal of air from the work area. The gases and particles in the air are thereby removed, and subsequent filtration or other cleansing operations can be employed downstream to permit subsequent disposal of the contaminants. A hood can be provided in association with each vacuum conduit and vacuum opening to reduce the amount of particles and gases that escape from the work area.
A large vacuum pump, with corresponding operating expense, is required to provide adequate vacuum to a number of work areas. Equipment in these areas, however, does not always operate continuously, but sometimes infrequently or intermittently. Vacuum flow from such work areas is wasted whenever the equipment is not in operation. Energy is lost by the needless withdrawal of air from these work areas on a continuous basis. Also, the size of the vacuum pump that is necessary for servicing these work areas is unnecessarily increased by the unnecessary generation of vacuum.
Manual shutters have been installed into the vacuum conduits of such systems to reduce the energy consumption caused by air being withdrawn from work areas having idle equipment. The shutters are often thin metal or plastic plates that are inserted transversely across the vacuum conduit when the respective equipment serviced by that conduit is not in use or is not in a contaminant-generating mode of operation. The air flow through the respective vacuum conduit is blocked, which advantageously causes a greater vacuum pull in the conduits where equipment is in use and vacuum is required. Many operators, however, forget or refuse to close the shutters as necessary, and leave the shutters open at all times. This causes a substantial loss of vacuum pull through those conduits where equipment is in use. The manual shutters are usually made of metal, and are known to sometimes bend or rust. Also, significant vibration noise can be generated by the loosely-fitted shutters.